Air power gives boats a lift

After a day of pleasure boating, having to pull your boat from the water using a hand crank is a nuisance similar to taking out the garbage - it's not especially difficult, but it's not something you look forward to, either. Matt Martin, a former agricultural and biological engineering student at Purdue University, West Lafayette, Ind., and Gary Krutz, professor of agricultural and biological engineering at Purdue, have come up with a better idea: a pneumatic lift that raises and lowers a boat without the use of electric motors.

Krutz said the device could replace electric motors currently used by boaters, and is much easier than hand-cranking a boat out of the water. "From a safety standpoint it makes sense because having an electrical hot wire on a boat dock presents potential problems."

Pneumatics offers safety, convenience

Krutz explained that maintaining electrical power at a private dock or small marina can be troublesome. "Everything gets moldy and green after two years. Then some varmint chews through the insulation during the winter, and when you turn it on in the spring you blow a fuse or experience problems even worse."

Martin surveyed local marinas to see if such a device would be useful and found it was. "They were all for a different method to raise boats because running conduit along the docks is always a problem," he revealed. Martin constructed the pneumatic boat lift using a standard air compressor, such as those found in local hardware stores. "We wanted to keep it simple," he continued, "and big compressors are very expensive."

The pneumatic boat lift was designed to work to standard friction drive boat lifts currently in use - it only replaces the electric motor, not the entire lift.

The boat lift is powerful enough to easily raise an 18-ft boat but can also accommodate a 21-ft boat or a pontoon boat, according to Krutz. "It's not designed to raise those 35-footers, but those only get lifted out of the water once a year anyway, he explained.

Although the compressor itself does use electricity, it can be placed away from the dock. Martin and Krutz designed the system to place the compressor 60 ft from the dock. In tests, however, they placed the compressor as far as 250 ft away from the dock and ran air hose to the dock to power the lift.

"There was very little loss of power," Krutz explained. "It was less of a power loss than if you had run an electrical line down to the dock."

Krutz expects an air-powered boat lift to cost about the same as an electrical one. "Electrical boat lifts cost around $600, and we built this prototype for $700, so I don't think producing one on a commercial scale would cost any more than what is on the market now," he explained.

Martin said having compressed air at the boat dock presents other advantages beyond the safety of removing electricity from a sensitive area. "Many boaters like to pull tubes behind their boats. This makes it easy to inflate a tube right at the dock. You can also attach a blow gun to the air line and clean out the boat at the end of the day."

Martin developed the pneumatic boat lift as his final senior engineering project for an Agricultural Equipment Design course at Purdue, which Krutz teaches.

Since graduating in May of 2002 with a degree in agricultural and biological engineering, with an emphasis in machine systems, Martin has worked for Turblex Inc. of Springfield, Mo., as an engineering project manager working on large industrial air compressors.

"The experience of my senior design project has helped tremendously in this position," he explained. "You get a real-world flavor from Professor Krutz's classes that is very valuable."